unfortunately I managed to set my nozzles too low and thereby ruined the BuildTak. Now I wonder what parts need replacement. Is it only the BuildTak Bed Tape (e.g. https://www.bilby3d.com.au/DispProd.asp ... apeBTr3dN2), or do I need to replace other pats as well? I am concerned that the glass underneath the black tape could have seen some damage as well. Is this likely to have happened; does anybody have experience with this? Also, how would one remove the tape from the glass platform underneath?

Couple of things to know:#1 glass is harder than brass, meaning in general, brass cannot scratch glass. Short of cracking and shattering the plate, no you did not hurt the glass.

#2 because the nozzle is softer than glass, a serious nozzle strike and dragging though buildtack and ramming hard into the glass can bend and damage the nozzle tip partially closing it off or distorting it. I'm not saying for sure it damaged the nozzle, just what "can happen". I would use the load filament with the hotend well above the bed and really in the front corner so the extruding hot noodle of plastic can just drop down, and observe the flow of the nozzle after this accident.

#3 replacing a nozzle is not a trivial task with the hotend system and is fragile. It is recommended that unless you really understand the mechanics here, understand what you can and cannot do and read the instructions and warning several times, buy a complete $80 hotend as a spare. https://www.raise3d.com/pages/instructi ... assembling and read warnings about how leaks are created, how folks snap off throat tubes forum.raise3d.com/viewtopic.php?f=4&t=6599&p=26953

#2 However I did not use the high temperature silicone grease, as there is no mention of this in the video, only in the written description. I would like to have one around for the next time I do this. Where would I get a high temperature silicon grease that would fulfil this very purpose, would you know?

#3 I did as you said, and I think I got really lucky and my nozzle is still alright.